The preparation of biological phenolic resin (PF) with green recyclable biomaterials instead of phenol is a research hotspot for solving current resource and environmental problems. In this study, on the basis of introducing lignin into the phenolic system, daidzein of a renewable resource with a rigid structure was selected to modify lignin-based phenolic resin (LPF), and the improvement of the mechanical and thermal properties of the modified phenolic resin under different substitution ratios was studied. The friction materials were prepared with a daidzein-modified lignin-based phenolic resin (D-LPF) as the matrix binder, and their effects on the mechanics and friction and wear properties of friction materials were investigated. The results show that when the proportion of daidzein replacing phenol is 12%, the highestTpcan reach 152.4 °C, and theTgof the modified D-LPF resins is significantly higher than those of PF and LPF. The highestTsof D-LPF is 203.3 °C, which is also significantly higher than those of PF and LPF (184.7 °C and 174.6 °C, respectively). The maximum carbon residue rate at 800 °C is 64.2% and is greatly improved compared with the 55.1% and 56.7% of PF and LPF. The bending strength and impact strength of D-LPF-matrix friction materials are obviously higher than those of PF- and LPF-matrix friction materials. The specific wear rate of D-LPF-matrix friction materials is 0.70 × 10−4mm3/Nm, which is obviously lower than those of PF- and LPF-matrix friction materials and shows good applicational prospect as a matrix resin in friction materials.
For the concern of sustainable and green chemical engineering , the development of flame retardants from renewable biomaterials is particularly attractive. Daidzein is an isoflavone found in large amounts in soybeans and other legumes. The structure of daidzein permits easy reaction with flame retardant groups and is beneficial for the formation of char at high temperature. A flame retardant which can work in both the gas phase and the condensed phase may be unusually effective. An organophosphorus flame retardant (DPOD) has been prepared using daidzein and diphenylphosphinyl chloride, and used to modify the flammability of epoxy (EP) resin. The structure and flame retardant mode of action of DPOD in EP were explored. The results showed that DPOD works in both the gas phase and the condensed phase and improves the flame retardancy of EP blends greatly. In addition, the DPOD doesn't deteriorate the glass transition temperature and impact strength of EP blends. This work is a useful attempt to use biobased monomers in the design of flame retardants.
Guangjian Dai,Shengtao Zhang,Wenjie Yang,Chunxiang Wei,SanE Zhu,Zhongxing Geng,Eric W. M. Lee,Hongdian Lu,Bin Yu,Wei Yang
The exploration of biomass-derived thermosetting resins for implementation in flexible electronic packaging has emerged as a central focus. Herein, a daidzein-derived monomer (DDAB) was synthesized, which featured carbon–carbon double bonds. Biobased resins, namely, DDAB/3SH and DDAB/4SH, were meticulously fabricated via photocuring process, entailing the amalgamation of DDAB with trithiol (TPTMP) and tetrathiol (PETMP) monomers, respectively. DDAB/4SH showed impressive mechanical properties with a tensile strength of 28.1 MPa and elongation at break of 21.3%. Notably, owing to the augmented free volume inherent within the system, DDAB/3SH exhibited an exceptional elongation at a break of 111.7%, thereby surpassing the performance metrics of the majority of previously documented thiol-containing compounds. Moreover, both DDAB/3SH and DDAB/4SH demonstrated desirable dielectric properties. Specifically, within the frequency range of 15–16 GHz, DDAB/3SH achieved a minimum dielectric constant of 2.58. The exceptional dielectric performance, coupled with the tunable mechanical properties, proves the substantial application potential of DDAB/SH biomass-derived resins for flexible electronic packaging applications.
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